Two-Stage Adjusting Member for Adjusting Slope of Seat Back

ABSTRACT

A two-stage adjusting member for adjusting slope of a seat back formed by a first stage adjusting member and a second stage adjusting member is disclosed. A user operates the first stage adjusting member so that the seat back reclines from 90 degrees to 70 degrees to the horizontal. Then the users operates the second stage adjusting member so as to make the seat back further incline backward such as 10 degrees more to another slope. Thus the seat back slope is adjusted in two stages and such design is much more safer for users and can prevent danger or harm caused by suddenly reclining.

BACKGROUND OF THE INVENTION

The present invention relates to an adjusting member for adjusting seatback slope, especially to a two-stage adjusting member for adjustingseat back slope that the user can operate a first stage adjusting memberto make the seat back recline a certain angle. Then by a second stageadjusting member, the seat back further reclines such as 10 degrees moreand becomes more close to a horizontal position. Thus the adjustment ofthe seat back is more safer.

There are various designs of adjustment mechanisms on office chairs suchas height adjustment mechanism for armrests, height adjusting member forseats, seat slope adjusting member, seat back slope adjusting member,height adjusting member for seat backs, or waist support adjustingmember, as prior arts disclosed in Taiwanese patent M321261, M326807,M308687, M3281531, M272463, M270739, M244008, M244006, M244008, 1227118,Taiwanese publication No. 00480961, 00312709, 00219466, 00148174,00051473, 0578518, 00444555, 306219, 296582, Chinese patent No.ZL99235672.5 and U.S. Pat. No. 6,994,400 etc. The seat height adjustmentmechanism and/or seat back slope adjustment mechanism are/is disposed ina main frame (first frame) of a base on bottom surface of the seat. Thenby a control rod extending from the base to the edge of the bottomsurface of the seat and on the left/right sides of the seat, the usercan operates the mechanisms by left or right hand according to theirneeds.

Now the reclining function of the office chair is getting more importantfor users, especially for persons who sit on the seat for long period oftime such as computer users. The office chair is not only a task chairbut also for multiple purposes such as lounge chairs and reclinerchairs. Thus the seat back of the office chair requires at least twokinds of slopes for users to choose. Generally, most of the seat backslope adjusting member available now is one-stage adjustment. That meansthe user adjusts the slope of the seat back only once. While adjustingthe chair, the users recline and decide which slope of the seat backthey require. However, the base of the office chair is disposed withrolling wheels. Thus the user may recline suddenly a large angle or toan almost flat position, fall backward and get hurts.

SUMMARY OF THE INVENTION

Therefore it is a primary object of the present invention to provide atwo-stage adjusting member for adjusting seat back slope that includes afirst frame whose top surface is fastened on the bottom surface of theseat, a second frame, a first stage adjusting member and a second stageadjusting member. A bottom surface of the first frame connects with asupporting mount. The rear end of the first frame is pivoted andconnected with the second frame. The first stage adjusting member in thetwo-stage adjusting member for adjusting seat back slope is used toadjust the slope of the seat back to a first stage slope. The front endof the second frame is pivoted and connected with the first frame whilethe rear end of the second frame is fastened and connected with the seatback. The second stage adjusting member is disposed between the firstframe and the second frame. The user operates the first stage adjustingmember so as to make the seat back recline an angle for users to lieface up. Furthermore, the user operates the second stage adjustingmember so that the seat back reclines from the first stage slope to thesecond stage slope. Thus the two-stage adjustment of the seat back ismuch more safer for users.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an embodiment of the present invention assembled on an officechair;

FIG. 2 is a perspective view of an embodiment according to the presentinvention;

FIG. 3 is a partial enlarged view of the embodiment in FIG. 2;

FIG. 4 is an explosive view of an embodiment according to the presentinvention;

FIG. 5 is an explosive view of a seat back depth adjusting member of anembodiment according to the present invention;

FIG. 6 is a schematic drawing showing a usage of an embodiment accordingto present invention;

FIG. 7 shows an embodiment of the present invention recline to a firststage slope;

FIG. 8 shows an embodiment of the present invention recline to a secondstage slope;

FIG. 9 shows a user lying face up in the embodiment in FIG. 8;

FIG. 10 shows a status before adjustment of an embodiment according tothe present invention;

FIG. 11 shows a status after adjustment of the embodiment in FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Refer from FIG. 1 to FIG. 4, a two-stage adjusting member for adjustingseat back slope 1 according to the present invention includes a firstframe 20, a second frame 30 and a second stage adjusting member 40. Thetwo-stage adjusting member for adjusting seat back slope 1 is disposedon a bottom surface 11 of a seat 10 and a rear end thereof extends toand fastened with a seat back 13 so that a certain angle formed betweenthe seat 10 and the seat back 13, as shown in FIG. 6.

A top surface of the first frame 20 is fastened on the bottom surface 11of the seat 10 while a bottom surface of the first frame 20 connectswith a supporting mount 12 standing on the ground. By a pivot 50, thefirst frame 20 is pivoted with the second frame 30. A first stageadjusting member 21 is disposed on the first frame 20 and the secondframe 30 is pivoted backward to a certain angle (about 20 degrees)around the pivot 50 by operation of a first adjustment rod 211. Thus theseat back 13 on top of the second frame 30 also reclines an angle A, asshown in FIG. 7. This is the first stage adjustment.

A front end of the second frame 30 is pivoted and connected with thefirst frame 20 by the pivot 50 while a rear end of the second frame 30is fastened with the seat back 13. Refer from FIG. 6 to FIG. 10, anelastic device 14 is formed by a spring and is used to adjust supportingstrength of the seat back 13 while the seat back reclining. That'selastic returning strength of the seat back 13 that enables the seatback 13 to turn back. Moreover, a seat back depth adjusting member 60 isdisposed on the second frame 30. The seat back depth adjusting member 60makes the seat back 13 move from an anterior position, as shown in FIG.10, to a rearward position, as shown in FIG. 11. In this embodiment, theseat back depth adjusting member 60 is formed by an upper housing and alower housing (60). A top surface 61 thereof is disposed with twovertical serrated slots 62 and stopping surfaces 63, as shown in FIG. 4& FIG. 5. The seat back depth adjusting member 60 corresponds to a stagecontrol device 64. The stage control device 64 includes an adjusting rod65 that inserts through and locates between two holes 33 of the secondframe 30. Two sets of positioning rings 66 and cams 67 are arranged onthe adjusting rod 65, respectively and symmetrically on the right andleft sides. That means each one side of the adjusting rod 65 is disposedwith one positioning ring 66 and one cam 67. Through an insertion hole34 on the second frame 30, the positioning ring 66 and one cam 67correspond to and work with the serrated slots 62 and the stoppingsurface 63. When the positioning ring 66 and one cam 67 are respectivelyreleased from the serrated slot 62 and the stopping surface 63, the seatback 13 is able to be adjusted forward or backward for changing depth.After moving to a certain depth, rotate the adjusting rod 65 so that thetwo sets of positioning rings 66 and cams 67 rotate synchronously andthe positioning ring 66 locks into one of the serrated slots 62 whilethe cam 67 presses against on the stopping surface 63 so as to finishoperation of the seat back depth adjusting member 60. Thus the space forseating or reclining of the seat is adjusted for improving comfort ofthe chair. Furthermore, a fixing member 68 is further disposed betweenthe upper and the lower housing (60), as shown in FIG. 5. Thus thefastening strength of the seat back depth adjusting member 60 with theseat back 13 is improved.

Refer to FIG. 4, the second stage adjusting member 40 is arrangedbetween the first frame 20 and the second frame 30. As shown in FIG. 7,when the seat back 13 reclines a certain angle A by the adjustment ofthe first stage adjusting member 21, the seat back 13 can recline afurther angle B such as 10 degrees, as shown in FIG. 8. Thus the usercan lie face up and take a good rest, as shown in FIG. 9. The secondstage adjusting member 40 includes a pin 41 formed by an inner end 411and an outer end 412 and being disposed between left and right holes 23of the first frame 20. The second frame 30 includes left and right holes31 a-31 b corresponding to the left and right holes 23 of the firstframe 20.

Moreover, the inner end 411 of the pin 41 connects to a handle 42 whilethe handle 42 is connected with a guide pin 46 which is disposed in aguiding hole 32 of the second frame 30 moveably. The pin 41 is arrangedwith an elastic member 43 such as spring and is restricted by a stoppingblock 44 so that the pin 41 can turn back automatically by elasticity ofthe elastic member 43 after movement. Furthermore, a projective rod 45on the pin 41 moves freely inside the hole 31 a of the second frame 30.Thereby, when the handle 42 is pulled outward horizontally by guiding ofthe guide pin 46, the outer end 412 of the pin 41 and the projective rod45 synchronously move outward and release from the hole 31 b and thehole 31 a of the second frame 30 respectively. Now the second frame 30further reclines an angle such as ten degrees from the slope of thefirst stage so that the slope of the second stage is achieved. Incomparison, the conventional adjusting member only has one stageadjustment and the chair may recline from a vertical position to almosta flat position suddenly. This may cause danger or harm to users.Instead, the present invention adjusts the slope of the seat back 13 intwo stages. By two-stage adjustment, the chair becomes much more safer.In addition, the second-stage slope can automatically turn back byelasticity of the spring of the elastic member 14, as shown from FIG. 6to FIG. 10. Thus it's convenient for users to adjust the slope of thechair from the second stage back to the first stage. And the pin 41 alsoturns back to the original position-into the holes 31 b, 31 aautomatically by the elasticity of the elastic member 43.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details, and representative devices shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. A two-stage adjusting member for adjusting seat back slope comprisinga first frame, a second frame and a second stage adjusting member;wherein a top surface of the first frame is fastened on a bottom surfaceof a seat while the bottom surface of the first frame connects with asupporting mount; the first frame is pivoted and connected with thesecond frame by a pivot on rear end thereof; a first stage adjustingmember in the first frame is used to adjust a seat back reclining to afirst stage slope; the second frame is pivoted and connected with thefirst frame by a pivot on front end thereof while a rear end thereof isfastened and connected with the seat back; the second stage adjustingmember is disposed between the first frame and the second frame so as tomake the seat back further reclines a certain angle after being adjustedby the first stage adjusting member; wherein the seat back reclinesbackward a certain angle by adjustment of the first stage adjustingmember and then further reclines backward a further angle to a secondstage slope so as to achieve safer adjustment of the seat back intwo-stages.
 2. The device as claimed in claim 1, wherein the secondstage adjusting member having a pin moveably disposed between left andright holes of the first frame and also between left and right holes ofthe second stage adjusting member while the left and right holes of thesecond stage adjusting member are corresponding to the left and rightholes of the first frame.
 3. The device as claimed in claim 2, whereinthe second stage adjusting member is disposed with a guide pin thatguides the pin moving in parallel between the left and right holes ofthe first frame and the corresponding left and right holes of the secondstage adjusting member.
 4. The device as claimed in claim 3, wherein oneend of the pin connects to a handle.
 5. The device as claimed in claim1, wherein the second stage adjusting member enables the seat backreclining backward ten degrees more.
 6. The device as claimed in claim1, wherein the second frame is disposed with a seat back depth adjustingmember formed by an upper housing and a lower housing; a top surface ofthe seat back depth adjusting member is disposed with two verticalserrated slots and two stopping surfaces; a stage control device isarranged on the second frame while the stage control device includes anadjusting rod that inserts through and locates between two holes of thesecond frame and two sets of positioning rings and cams are arranged onthe adjusting rod, respectively and symmetrically on the right and leftsides of the adjusting rod; through an insertion hole on the secondframe, the positioning ring and one cam correspond to and work with theserrated slots and the stopping surface; when the positioning ring andone cam are respectively released from the serrated slot and thestopping surface, the seat back is able to be adjusted forward orbackward; after moving to a certain depth, the adjusting rod is rotatedso that the two sets of positioning rings and cams rotate synchronouslyand the positioning ring locks into one of the serrated slots while thecam presses against and fixes on the stopping surface.